According to preliminary data from the National Center for Health Statistics, the birth rate fell to its lowest point since 1920, the first year they started keeping track. Analysis by the Pew Research Center closely ties the decline to the downturn in the economy, starting around 2008.

The birth rate is the annual number of births per 1,000 women in the prime childbearing ages of 15 to 44. It was 63.2 in 2011, a dip of 8% since 2007. This decrease is led by immigrant women, who experienced a 14% drop in fertility rates since 2007. Mexican women comprised the steepest decline, at 23%.

"If you apply the common sense lens here, when it comes to decisions about when to have children, how many and how to space them, the economy clearly matters," said Bill Albert, spokesman for the National Campaign to Prevent Teen and Unplanned Pregnancy, told CNN. It’s unclear how much of a role the trend to marry later in life, and farther into a woman’s fertility window, is playing.